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arch/arm: fix the error in obtaining thread pointer after we use -mtp=soft #17815

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Merged
xiaoxiang781216 merged 2 commits into from
Jan 9, 2026
+37 −9
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arch/arm: fix the error in obtaining thread pointer after we use -mtp=soft #17815

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654aae0
arch/arm: Refactor __aeabi_read_tp to ensure EABI compliance
suoyuanG Jan 9, 2026
627ad4b
arch/arm: Fix TLS initialization to account for padding between sections
suoyuanG Jan 9, 2026
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46 changes: 37 additions & 9 deletions arch/arm/src/common/arm_tls.c
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Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,24 @@

#include "arm_internal.h"

/****************************************************************************
* Private Function
****************************************************************************/

/****************************************************************************
* Name: arm_read_tp
*
* Description:
* Helper function for __aeabi_read_tp.
* This allows tls_get_info() macro to expand properly.
*
****************************************************************************/

void *arm_read_tp(void)
{
return (void *)(tls_get_info() + 1);
}

/****************************************************************************
* Public Functions
****************************************************************************/
Expand All @@ -51,7 +69,7 @@ int up_tls_size(void)

return sizeof(struct tls_info_s) +
sizeof(void *) * 2 +
sizeof(uint32_t) * (_END_TBSS - _START_TDATA);
(_END_TBSS - _START_TDATA);
}

/****************************************************************************
Expand All @@ -67,15 +85,12 @@ int up_tls_size(void)

void up_tls_initialize(struct tls_info_s *info)
{
uint8_t *tls_data = (uint8_t *)(info + 1);

uint32_t tdata_len = sizeof(uint32_t) * (_END_TDATA - _START_TDATA);
uint32_t tbss_len = sizeof(uint32_t) * (_END_TBSS - _START_TBSS);

tls_data += sizeof(void *) * 2;
uint8_t *tls_data = (uint8_t *)(info + 1) + sizeof(void *) * 2;
uint32_t tdata_len = _END_TDATA - _START_TDATA;
uint32_t tbss_len = _END_TBSS - _START_TBSS;

memcpy(tls_data, _START_TDATA, tdata_len);
memset(tls_data + tdata_len, 0, tbss_len);
memset(tls_data + tdata_len + (_START_TBSS - _END_TDATA), 0, tbss_len);
}

/****************************************************************************
Expand All @@ -84,9 +99,22 @@ void up_tls_initialize(struct tls_info_s *info)
* Description:
* Read thread local storage region pointer.
*
* This function follows the ARM EABI specification for TLS helper
* functions:
* - Only r0 is modified (return value)
* - r1-r3 must be preserved for the caller
*
* The naked attribute ensures strict register usage compliance.
*
****************************************************************************/

__attribute__((naked))
void *__aeabi_read_tp(void)
{
return (void *)(tls_get_info() + 1);
__asm__ __volatile__
(
"push {r1-r3, lr}\n\t"
"bl arm_read_tp\n\t"
"pop {r1-r3, pc}\n\t"
);
}
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